<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        html,body{
            height: 100%;
            margin: 0;
            padding: 0;
        }
        div:nth-child(1){
            height: 50px;
            margin: 10px 0px;
        }
        p{
            width: 200px;
            height: 50px;
            text-align: center;
            font: 18px/50px 宋体;
            color: white;
            background-color: red;
            margin: 0 auto;
            border-radius: 5px;
            display: none;
        }

        div:nth-child(2){
            width: 200px;
            height: 100%;
            text-align: center;
            box-sizing: border-box;
            margin: 0 auto;
        }
        input:nth-child(1){
            border: 1px solid #000;
            width: 200px;
            height: 40px;
            font: 14px/40px 宋体;
            color: black;
        }

        input:nth-child(2){
            border: 1px solid #000;
            width: 80px;
            height: 40px;
            font: 14px/40px 宋体;
            color: black;
        }

        input:nth-child(3){
            border: 1px solid #000;
            width: 116px;
            height: 45px;
            font: 14px/40px 宋体;
            color: black;
            margin-top: 2px;
        }
    </style>
</head>
<body>
    <div><p>有误，请重新输入</p></div>
    <div>
        <input type="text" placehold="请输入手机号">
        <input type="text" placehold="请输入验证码"><input type="button" value="获取验证码">
    </div>
</body>
</html>

<script type="text/javascript" src="js/jquery-3.0.0.min.js"></script>
<script type="text/javascript">
    $(window).ready(function () {
        $('div input').eq(0).on("blur",function () {
             console.log(this);
             console.log(this.val());
        });

        $('div input').eq(2).on('click',function () {
            var content = $('div input').eq(1).val();
            console.log(content);
            if(content === '' || content === null) {
                $('div p').fadeIn(1000).delay(1000).fadeOut(1000);
            }
        });
    });
</script>